class Settings():
    """存储《外星人入侵》的所有设置"""

    def __init__(self):
        """初始化游戏设置"""
        #屏幕设置
        self.screen_width = 800
        self.screen_height = 600
        self.bg_color = (230,230,230)
        #飞船的设置
        self.ship_speed_factor = 1.5

        #子弹设置
        self.bullet_speed_factor = 1
        self.bullet_width = 3
        self.bullet_height = 15
        self.bullet_color = 60,60,60
        self.bullets_allowed = 3

        #外星人速度
        self.alien_speed_factor = 1
